Rolls Edmund T, Verhagen Justus V, Kadohisa Mikiko
Department of Experimental Psychology, University of Oxford, Oxford OX1 3UD, United Kingdom.
J Neurophysiol. 2003 Dec;90(6):3711-24. doi: 10.1152/jn.00515.2003. Epub 2003 Aug 13.
The primate orbitofrontal cortex (OFC) is a site of convergence from taste, olfactory, and somatosensory cortical areas. We describe a population of single neurons in the macaque OFC that responds to the texture of food in the mouth. Use of oral viscosity stimuli consisting of carboxymethylcellulose (CMC) in the range 1-10,000 centipoise showed that the responses of one subset of these neurons were related to stimulus viscosity. Some of the neurons had increasing responses to increasing viscosity, some had decreasing responses, and some neurons were tuned to a range of viscosities. These neurons are a different population to oral fat-sensitive neurons, in that their responses to fats (e.g., safflower oil), to silicone oil [(Si(CH3)2O)n], and to mineral oil (hydrocarbon) depended on the viscosity of these oils. Thus there is a dissociation between texture channels used to sense viscosity and fat. Some of these viscosity-sensitive single neurons were unimodal (somatosensory; 25%) and some received convergent taste inputs (75%). A second subpopulation of neurons responded to gritty texture (produced by microspheres suspended in CMC). A third subpopulation of neurons responded to capsaicin. These results provide evidence about the information channels used to represent the texture and flavor of food in a part of the brain important in appetitive responses to food and are relevant to understanding the physiological and pathophysiological processes related to food intake, food selection, and the effects of variety of food texture in combination with taste and other inputs that affect food intake.
灵长类动物的眶额皮质（OFC）是味觉、嗅觉和体感皮质区域的汇聚部位。我们描述了猕猴眶额皮质中的一群单神经元，它们对口腔中食物的质地有反应。使用由粘度在1至10000厘泊范围内的羧甲基纤维素（CMC）组成的口腔粘度刺激物表明，这些神经元的一个子集的反应与刺激粘度有关。一些神经元对粘度增加的反应增强，一些则反应减弱，还有一些神经元对一定范围的粘度进行调谐。这些神经元与口腔脂肪敏感神经元不同，因为它们对脂肪（如红花油）、硅油[（Si(CH3)2O）n]和矿物油（碳氢化合物）的反应取决于这些油的粘度。因此，用于感知粘度和脂肪的质地通道之间存在分离。这些对粘度敏感的单神经元中，一些是单峰的（体感；25%），一些接受汇聚的味觉输入（75%）。第二个神经元亚群对颗粒质地（由悬浮在CMC中的微球产生）有反应。第三个神经元亚群对辣椒素有反应。这些结果为大脑中一个对食物的食欲反应很重要的部分中用于表征食物质地和风味的信息通道提供了证据，并且与理解与食物摄入、食物选择以及各种食物质地与味觉和其他影响食物摄入的输入相结合的效果相关的生理和病理生理过程有关。
